This proposed work is to analyze contraints on naturally occurring as well as non naturally occurring nucleotide sequences. The existence of constraints is evidence for the theory of Genotypic Selection, as proposed by the principal investigator. Unknown regions of bacteriophage DNA will be sequenced and analyzed for constraints that allow prediction of function. The sequencing method will be the Sanger-Coulson dideoxy method and a novel gel system developed by the principle investigator. Computer programs will be developed and inter-locked in order to store, retrieve, analyze, and graph large nucleotide sequences. Optimum algorithms we have developed will be employed in combinatorial searches.